The present invention relates to a traffic sign recognition system.
For safe driving etc., it is undesirable to be unaware of a traffic sign installed on a road. JP2014-120111A discloses an art in which a detector for detecting a line of sight of a driver driving a vehicle is provided and if a viewing direction (line of sight) of the driver is different from a direction of a traffic sign ahead of the vehicle, it is considered that the traffic sign is not viewed by the driver and caution information is displayed.
Among a variety of types of traffic signs, there are warning signs mainly illustrated in yellow. Some of various kinds of warning signs which indicate road situations ahead of vehicles indicate a slippery road condition, existence of a sharp curve, a road intersection or branching, a narrowing road width (e.g., merging of lanes), road under construction, a high possibility of rocks falling, etc.
With the art described in JP2014-120111A, when the viewing direction of the driver is toward the traffic sign, the traffic sign is considered as viewed and caution information regarding the traffic sign is not displayed. However, even if the viewing direction of the driver is toward the traffic sign, it does not mean that the driver sufficiently understands the contents of the traffic sign. If the contents of the traffic sign are for bringing high attention to a road condition ahead of the vehicle, it is desirable to lower a vehicle speed or refrain from sharp acceleration. Especially if a road surface condition is slippery, since a behavior of the vehicle may become unstable due to acceleration or change in steering, it is desirable to enhance the understanding of the traffic sign by the driver.